Case histories of ground improvement schemes in roadworks relevant to railroad embankments

Abstract

Australia's first trains designed 200 km/h are being delivered to Western Australia for the TransWA country rail system (Hammond, 2003). The construction of a railroad structure in soft clays in itself is a significant cost, and many design problems are caused by the requirements that the railroad embankment be visible and noise controlled. In this paper case histories of the use of ground improvement schemes to improve the behaviour of soft clays in Malaysia, Thailand (Bangkok) and Queensland are presented. Of the many possible ground improvement techniques, embankments with prefabricated vertical drains were found to be effective in improving the soft clay behaviour as revealed from the experience in Malaysia, Thailand and Queensland. Stone columns and sand compaction piles are only used in limited cases, with test embankments and further studies needed to refine the techniques and to make them more appropriate. According to the European experience (in particular those in Scandinavia) and Japan, the use of shallow and deep stabilization are emerging as the most commonly used techniques to be adopted in ground improvement works related to railroad embankments. Laboratory studies and field performance data related to the use of lime and cement stabilization are also included in this paper.